Method of manufacturing a multiple layer directionally oriented nonwoven fiber material

ABSTRACT

Disclosed herein are embodiments of a multi-layer nonwoven fiber material, and related methods of manufacturing the material. In one exemplary embodiment, the fiber material includes a first layer of directionally aligned fibers together with a second layer of randomly dispersed fibers dispersed over the first layer. Consistent with one exemplary method for manufacturing a nonwoven fiber material, the method includes dispersing a first plurality of fibers horizontally in one or more predetermined directions, as well as dispersing a second plurality of fibers horizontally in random directions. In such an embodiment, the second plurality of fibers is dispersed over the first plurality of fibers. Moreover, an exemplary embodiment of a roofing shingle employing a nonwoven fiber material as described herein is as disclosed.

RELATED APPLICATIONS

The present application is a Divisional Application of, and thus claimspriority to, application Ser. No. 11/941,440, filed Nov. 16, 2007, whichclaims priority to application Ser. No. 10/726,461, filed Dec. 3, 2003,now U.S. Pat. No. 7,309,668, the entire contents which are incorporatedherein in its entirety, for all purposes.

TECHNICAL FIELD

Disclosed embodiments herein relate generally to nonwoven fibermaterials, and more particularly to a multiple layer nonwoven fibermaterial and methods of manufacturing the same.

BACKGROUND

Nonwoven products have gained continued acceptance in the industry for awide range of applications, particularly as replacements for wovenfabrics. The term “nonwoven” refers to textile structures produced bybonding or interlocking fibers (or both) accomplished by mechanical,chemical, thermal or solvent means, or even combinations thereof. Suchtextile structures do not include paper or fabrics that are woven,knitted or tufted. Typically, nonwoven materials are composed of simplya single layer of randomly oriented fibers. Examples of productsemploying nonwoven materials to date include facings or top-sheets indiapers, incontinent pads, bed pads, sanitary napkins, hospital gowns,cleaning towels, carpets, draperies and industrial and commercial goods,such as wipe cloths, tire cords, conveyor belts, and hospital fabrics.It is typically desirable to produce the nonwoven material so that ithas the flexibility and hand softness of a textile, yet is as strong aspossible.

Conventional processes for manufacturing nonwoven materials, such asnonwoven glass fiber materials employed in roofing shingles, as well asother products, typically follow a similar approach. Specifically, aslurry of glass fibers is made by adding glass fiber strands to a pulperto disperse the fiber in the white water. The slurry mixture is thendeposited onto a “forming wire” and dewatered to form a continuous wetnonwoven fibrous mat. To dewater the slurry, the water is drawn throughthe forming wire, leaving the fibers from the slurry randomly dispersedover the forming wire to form the mat. A binding agent may then beapplied to the wet mat to bond the randomly dispersed fibers in theirrespective locations and directions. The mat material is then cut to adesirable size and dried. Alternative forming methods include the use ofwell-known “wet cylinder” forming, and “dry laying” using carding orrandom fiber distribution.

Although conventional nonwoven materials are typically stronger andresist tears more than woven materials, the density and/or number offibers (i.e., the “weight” of the material) used to form the materialoften must be further increased to satisfy some intended uses. Morespecifically, while a nonwoven mat may be stronger than a similar wovenmat, the nonwoven mat's weight may need to be increased to accommodateeven further stresses. Unfortunately, as the weight of nonwovenmaterials is increased to accommodate higher stresses, the cost ofmanufacturing also increases.

It is thus highly desirable to provide for a nonwoven material that canbe manufactured with less weight than conventionally available mats, butwith equivalent strengths. To do so would allow for advantageousdecreases in the cost of manufacturing an adequately strong nonwovenmaterial.

BRIEF SUMMARY

Disclosed herein are embodiments of a multi-layer nonwoven fibermaterial, and related methods of manufacturing the material. In oneexemplary embodiment, the fiber material includes a first layer ofdirectionally aligned fibers together with a second layer of randomlydispersed fibers dispersed above the first layer. In another exemplaryembodiment, the fiber material includes a first plurality of fibershorizontally dispersed in one or more predetermined directions. Inaddition, the fiber material includes a second plurality of fibershorizontally dispersed over the first plurality of fibers in randomdirections. In this embodiment, the fiber material still furtherincludes binding material binding the first and second pluralities offibers in their respective directions.

Methods for manufacturing a fiber material are also disclosed. Forexample, a disclosed method includes dispersing a first plurality offibers horizontally in one or more predetermined directions, as well asdispersing a second plurality of fibers horizontally in randomdirections. In this method, the second plurality of fibers is dispersedover the first plurality of fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the following detailed description of thepreferred embodiments, taken in conjunction with the accompanyingdrawings. It is emphasized that various features may not be drawn toscale. In fact, the dimensions of various features may be arbitrarilyincreased or reduced for clarity of discussion. In addition, it isemphasized that some components may not be illustrated for clarity ofdiscussion. Reference is now made to the following descriptions taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates an isometric view of one exemplary embodiment of atwo-layer nonwoven fiber material;

FIG. 2 illustrates is a side sectional view of the two-layer nonwovenfiber material illustrated in FIG. 1;

FIG. 3 illustrates a close-up view of an exemplary embodiment of a firstlayer of randomly distributed fibers of a nonwoven material formed overdirectionally aligned fibers;

FIG. 4 illustrates a top view of an exemplary pattern of theprotuberances on a forming wire used to produce the directionallyaligned fibers illustrated in FIG. 3;

FIG. 5 illustrates a top view of another exemplary embodiment of apattern of protuberances on a forming wire;

FIG. 6 illustrates a top view of yet another exemplary embodiment of apattern of protuberances on a forming wire;

FIG. 7 illustrates a top view of still another exemplary embodiment of apattern of protuberances on a forming wire; and

FIG. 8 illustrates an exemplary embodiment of a roofing shinglemanufactured using a nonwoven material as disclosed herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring initially to FIG. 1, illustrated is an isometric view of oneexemplary embodiment of a two-layer nonwoven fiber material or mat 100.The mat 100 includes a first layer 110 and second layer 120 composed ofnonwoven glass fibers. Although glass fibers have been used in theillustrated embodiment, other embodiments of the mat 100 may be formedfrom other types of fibers. Typically, the type of fibers employedvaries depending on the desired application of the mat 100. In otherexemplary embodiments, synthetic polymer fibers (e.g., polyester fibersor polyester-glass blend fibers), ceramic and inorganic fibers, naturalfibers, cellulosic fibers, and mixtures of any or all thereof may beemployed to form the mat 100. It should also be noted that although thefirst and second layers 110, 120 are shown as two separate layers of themat 100, the second layer 120 is actually typically formed over thefirst layer 110, typically in situ.

As illustrated, the mat 100 includes a first layer 110 of nonwovenfibers. Specifically, the first layer 110 is formed from a plurality ofdirectionally aligned fibers. In the illustrated embodiment, the firstlayer 110 of the mat 100 includes fibers that are directionally alignedin a plurality of linear formations. More specifically, in thisembodiment, the linear formations are actually a plurality of crossinglinear formations, crossing in two distinct directions. While the twodirections are perpendicular to one another, in the exemplaryembodiment, numerous other arrangements may also be employed. Inaddition, the number of linear formations used to form the first layer110, as well as their respective directions, is not limited to only twodirections, as discussed in greater detail below.

The mat 100 of FIG. 1 also includes a second layer 120 comprised ofrandomly dispersed fibers, i.e., a plurality of fibers arranged in anyof a number of random directions. As such, the randomly dispersed fiberslay among and upon one another in the manner typically found inconventional nonwoven fiber materials. The second layer 120 of fibers isformed over the first layer 110 of directionally aligned fibers, and ispreferably formed to a substantially uniform thickness across the entirelayer. Such uniformity provides for uniform strength characteristicsacross the entire second layer 120.

As with the second layer 120, the fibers in the first layer 110 may bedeposited such that the first layer 110 also has a substantially uniformthickness thereacross. Such an embodiment typically providessubstantially uniform strength characteristics across the entire firstlayer 110. Moreover, when both the first and second layers 110, 120 havea substantially uniform thickness, the entire mat 100 benefits fromsubstantially uniform strength characteristics across its entirety.

Looking now at FIG. 2, illustrated is a side sectional view of thetwo-layer nonwoven fiber material 100 illustrated in FIG. 1. Asillustrated, the second layer 120 of fibers is formed over the firstlayer 110 of fibers, and both have been formed to a substantiallyuniform thickness. For clarity of discussion, it should be appreciatedthat this sectional view of the mat 100 only illustrates one set oflinear formations 210 within the first layer 110, rather than showingboth sets of linear formations.

By only illustrating one set of linear formations 210, FIG. 2 moreclearly illustrates the directional alignment of the fibers comprisingthe linear formations 210. More specifically, FIG. 2 shows the linearformations 210 as viewed from one end of the formations 210. Only endsof the fibers (one of which is designated 220) forming the first layer110 are therefore visible from this view, since the fibers 210 aredirectionally aligned in the same direction as the linear formations210. As a result, the linear formations 210 are formed in long, narrowstrands of multiple directionally aligned and horizontally dispersedfibers 220 extending across the mat 100.

Also illustrated in FIG. 2 is an exemplary forming wire 230. Asmentioned above, the forming wire 230 is employed to form the mat 100.The exemplary forming wire 230 is specifically designed for formation ofthe mat 100. Specifically, conventional forming wires typically comprisea simple and substantially flat screen on which the fibers in a slurrycome to reset in a random orientation as the water 250 is drawn orotherwise removed from the slurry through the forming wire. In contrast,the forming wire 230 provided herein includes a similar flat portion,but also includes raised forming protuberances (an exemplary one ofwhich is labeled 240) extending from the flat portion of the formingwire 230.

In this exemplary embodiment, the forming protuberances 240 form groovesor channels in the forming wire 230 having a depth of about 0.063inches. In the same embodiment, the forming protuberances 240 may bearranged to form grooves therebetween having a width of about 0.1165inches. By employing forming protuberances 240 on the forming wire 230,as the water 250 is removed from the slurry and the fibers come to reston the forming wire 230, initial ones of the fibers are aligned by andbetween the forming protuberances 240. Once these fibers are aligned,they come to rest on the flat portion of the forming wire 230 in betweenthe forming protuberances 240, thus forming the linear formations 210 ofdirectionally aligned fibers of the first layer 110.

After the spaces in between the forming protuberances 240 are filledwith fibers directionally aligned to lay therebetween, the thickness ofthe linear formations 210 substantially equals the height of the formingprotuberances 240. At this point in the manufacturing process, theremaining fibers in the slurry can no longer be aligned between theforming protuberances 240 as the water 250 continues to be removedthrough the forming wire 230. Thus, the remaining fibers begin tohorizontally disperse randomly over both the tops of the formingprotuberances 240, as well as over the linear formations 210. Thisrandom dispersion of fibers results in the second layer 120 having therandomly oriented fibers discussed above formed over the first layer110.

In a specific exemplary embodiment, the overall thickness of the mat 100is about 0.035 inches, and the first layer 110 comprises a thickness ofonly about 0.002 inches to about 0.010 inches, as measured from thesecond layer 120, of the total thickness of the mat 100. Of course, anonwoven material constructed according to the principles disclosedherein is not limited to any particular thickness for the first layer110, nor any particular overall thickness for the material itself Infact, in some embodiments, the thickness of the first layer 110 is about50% of the overall thickness of the mat 100. Moreover, one factor thatmay be used in selecting the thickness of the first layer 110 is thedesired overall weight of the material of a desired thickness.Specifically, since the first layer 110 is composed of only linearformations with spaces therebetween defined by the protuberances 240,the overall weight of the first layer 110 would be less than an equallythick conventional layer formed with randomly dispersed, but similarlysized, fibers. Although having less weight, the directionally alignedfibers in the first layer 110 will typically provide greater strengthcharacteristics than a material formed with random fibers having thesame thickness. Examples of such differences in strength are explored infurther detail below.

Once the two layers 110, 120 of fibers have been formed using theforming screen 230 and the disclosed process, an aqueous bindingmaterial may then be applied to the nonwoven material. In suchembodiments, the binding material is distributed among the fibers withinthe first and second layers 110, 120 in order to bond the individualfibers in their respective locations. For example, the binding materialemployed may be comprised of an organic compound, such as, but notlimited to, acrylic latex, urea-formaldehyde, SBR latex, acrylicemulsions, and mixtures thereof. Of course, other appropriate types ofbinding agents may also be used to hold the fibers in position after thematerial is formed.

The nonwoven material may next be dried to remove any remaining waterand to cure (e.g., polymerize) the binding material when such materialis used. The drying may be accomplished using high-powered heat machinesconfigured to direct heated air across the nonwoven material, but othertechniques are also within the broad scope of the present disclosure.For example, in a drying and curing oven, the nonwoven material may besubjected to temperatures of 250-500° F., for periods usually notexceeding 4 to 5 minutes, to produce a cured, flexible, nonwoven fibermaterial.

Finally, the nonwoven material may be cut to a desired size. Preferably,a precision cut is performed on the finished nonwoven material toprovide a finished width for the nonwoven fiber material. Such aprecision cut allows the nonwoven material to be precisely trimmed to adesirable size (width), depending on the intended use of the material,without excessive waste of material. Moreover, the nonwoven material maybe cut into a plurality of mats having a specific length, as well aswidth. For example, if the nonwoven material is to be used in roofingshingles, the material may be cut to the desired length at this point inthe process. Alternatively, the entire length of nonwoven material maysimply be rolled into a large roll for shipment, and then cut to thedesired length(s) once received at another location.

Turning now to FIG. 3, illustrated is a close-up view of an exemplaryembodiment of directionally aligned fibers of a nonwoven material 300.More specifically, the close-up view of FIG. 3 shows a plurality ofintersections between three sets of linear formations 310. In such anembodiment of a nonwoven fiber material 300, the linear formations 310may be formed so as to intersect at any of a variety of angles.

The alignment of each set of linear formations 310 with respect to oneanother, and thus the angles of intersection between the sets, may beselected through the pattern present on the forming wire used to formthe nonwoven material 300. However, in addition to the orientation ofthe sets of linear formations 310, other factors to be considered indetermining the final strength of such material 300 include width andheight of each of the linear formations 310. Specifically, the amount ornumber of fibers included in each of the linear formations 310 may beadjusted depending on the desired strength, size, and overall weight ofthe final nonwoven material 300.

In this specific exemplary embodiment, three sets of exemplary linearformations 310 are illustrated, with each set aligned in a specificcorresponding direction. In a specific example, the fibers that arehorizontally aligned to create the linear formations 310 are fibershaving a diameter ranging from about 0.00001 inches to about 0.00100inches, and in a more specific embodiment, they are glass fibers rangingfrom about 0.0004 inches to about 0.0007 inches. In other embodiments,even wood fibers having a diameter as large as about 0.0300 inches mayalso be employed, and a nonwoven material constructed according to theprinciples disclosed herein is not limited to any particular fiber, ordiameter of fiber. In addition, each of the fibers comprising the linearformations 310 may have a chopped length ranging from about 0.10 inchesto about 1.5 inches; in this example, the fibers have a length of about1 inch. Moreover, as with the mat 100 in FIG. 2, the material 300 may beformed to a final thickness, including both the first and second layers,of about 0.035 inches, with the linear formations 310 (i.e., the firstlayer) having a thickness of about 0.002 to 0.010 inches. Furthermore,the exemplary material 300 also includes binding material to bond thefibers in position, where the binding material comprises about 5%-30% ofa total weight of the fiber material.

Manufacturing such an exemplary nonwoven material 300 results in amaterial having a tear-strength under the Elmendorf Tear Test greaterthan a single layer fiber material having a substantially equal totalthickness and weight, and comprising only randomly dispersed similarfibers. More specifically, Table 1 sets forth a comparison of testresults (using standard industry tests) between a conventional nonwovenfiber material, which is comprised of a single layer of randomlydispersed fibers, and a nonwoven fiber material constructed using theprinciples disclosed herein. For both materials, 15% of the weight ofthe material is binder material (Borden 413F® in this experiment), andthe overall weight of each of the materials is 1.6 lb/square. Inaddition, in Table 1 “σ Tears” means the standard deviation in tearstrength for n samples, and “σ Tensile” means the standard deviation intensile strength for n samples. Also, the “Mean Tear” and “Mean Tensile”measurements are an average taken over a number of samples tested, n.

TABLE 1 1.6 lb/square mat σ 15% binder Mean % σ Tensile, % Tensile,(Borden 413F) Tear, g Change Tear, g n lb/3″ Change lb/3″ n Conventional326 — 119 24 111 — 10 12 Single Layer Nonwoven Novel Two-Layer 393 ↑21%123 24 94 ↓15% 19 12 Directional Nonwoven

As is visible from the experimental results set forth in Table 1, thenonwoven fiber material 300 disclosed herein clearly has increased tearstrength at a slight expense of tensile strength relative to the samemass (e.g., amount of fibers) of a conventional nonwoven material.Moreover, since the disclosed nonwoven material typically has strongercharacteristics over conventional nonwoven materials, a material havinga lower fiber weight than such conventional materials may be constructedaccording to the processes disclosed herein. In such embodiments, theweight of the novel material may be significantly less than that ofcomparable conventional materials, yet selected so that the novelmaterial retains the same tear and tensile characteristics found in theconventional material.

Since a primary portion of the costs associated with manufacturingnonwoven materials is the amount of fibers used, the principlesdisclosed herein may be employed to secure significant savings inmanufacturing costs by providing a comparably strong nonwoven materialhaving significantly less weight or mass than conventional materials.The manufacturing savings would be especially substantial tomanufacturers producing volumes of nonwoven materials. The principlesdisclosed herein may also be employed with respect to weaker fibers (andconsequently less expensive) to provide for nonwoven materials havingsubstantially similar strength characteristics relative to conventionalnonwoven materials of the same weight, but using stronger fibers.

Turning now to FIG. 4, illustrated is a top view of an exemplary pattern400 of the protuberances on a forming wire used to produce thedirectionally aligned fibers 310 illustrated in FIG. 3. As illustrated,the protuberances (one of which is labeled 410) may be substantiallyround when viewed from the top, but the principles for manufacturing thenovel nonwoven material are not limited to any particular shape for theprotuberances. As may be seen in FIG. 4, the specific arrangement of theprotuberances 410, as well as the spacing selected therebetween, may beselected so as to provide three exemplary major linear formations 310 ofhorizontal, directionally aligned fibers. In addition, the pattern 400provides the opportunity for minor linear formations 420 (e.g., havingless fibers, and thus smaller, than major linear formation 310) alignedin other directions.

Providing multiple linear formations in crossing directions increasesthe strength characteristics of a nonwoven material manufactured usingthe disclosed methods, since tears (or other stresses) experiencedacross the material will typically have to cross at least one of thelinear formations. Since multiple fibers are directionally aligned toform the linear formations 310, tearing across the linear formations 310is substantially resisted. More specifically, in a nonwoven materialmade from only randomly dispersed fibers, tears or other stresses acrossthe material will put stress directly across some fibers, while much ofthe stress will be applied between fibers that extend in the samedirection as the tear. Stress applied in such directions simply worksagainst the binding material and separates the adjacent fibers. Incontrast, tears and other stresses applied across the linear formations310 provided herein have to work to break the aligned strands of fibersforming the linear formation 310, as well as the binding material. Avariety of forming wires may be constructed and utilized to formnonwoven materials constructed with the principles disclosed herein. TheFIGS. 5-7 each provides exemplary embodiments of protuberance patternsthat may be employed in a forming wire.

Turning next to FIG. 5, illustrated is a top view of another exemplaryembodiment of a pattern 500 of protuberances on a forming wire. Thearrangement of the pattern 500 in FIG. 5 is similar to that of thepattern 400 illustrated in FIG. 4 in that both have arrangements ofprotuberances that follow a Cartesian coordinate layout. However, thespacing of the protuberances in the pattern 500 differs such that onlytwo major linear formations 510 are formed, each on a diagonal, and twominor linear formations 520 are formed, each offset 45° from the majorlinear formations 510. In such an embodiment, the two major linearformations 510 are perpendicularly oriented with respect to one another,while the two minor linear formations 520 are as well.

Moreover, the orientation of the linear formations 510, 520 with respectto the edges of the finished nonwoven material may be selected with theexpected path(s) of potential tears in mind. This may be accomplished byselecting the arrangement of the protuberances on the forming wire basedon the desired orientation of the linear formations 510, 520. As such,the pattern 500 may be created so that the directions of expected tearsare perpendicular to one or more of the major linear formations 510,520, thus further increasing resistance to tears and other stresses.

Looking now at FIG. 6, illustrated is a top view of yet anotherexemplary embodiment of a pattern 600 of protuberances on a formingwire. The particular arrangement of protuberances for this pattern 600is also arranged in a Cartesian coordinate layout. However, twice thenumber of protuberances are employed, as compared to the pattern 500 inFIG. 5. As a result of this arrangement, only two major linearformations 610 are formed, this time each on a perpendicular to thematerial edges, while two minor linear formations 620 are formed, eachon a diagonal and offset 45° from the major linear formations 610. Aswith the pattern 500 in FIG. 5, in this embodiment, the two major linearformations 610 are perpendicularly oriented with respect to one another,while the two minor linear formations 620 are as well.

Moreover, because more protuberances are employed in the illustratedpattern, the spacing of the grooves defining the widths of the linearformations 610, 620 may be smaller than found in other patterns. Ofcourse, in some embodiments, while more protuberances may be used, thepattern may provide for a greater spacing therebetween. Thus, in allembodiments of a forming wire designed for use under the principlesdisclosed herein, the arrangement of the protuberances may be selectedfor a desired directional layout of linear formations 610, 620, whilethe spacing between protuberances (and their height) may be selected tochange the dimensions of the linear formations 610, 620 themselves.

Turning to FIG. 7, illustrated is a top view of still another exemplaryembodiment of a pattern 700 of protuberances on a forming wire inaccordance with the principles disclosed herein. Rather than arrangingthe plurality of protuberances in a Cartesian coordinate layout, as withthe forming wires in FIGS. 4-6, the pattern 700 illustrated in FIG. 7 isarranged using a triangular coordinate layout. As a result of this typeof arrangement, three major linear formations 710 of fibers may becreated in the nonwoven material. Moreover, in this embodiment, thelinear formations 710 intersect substantially equally at 60° from eachother, providing a uniform layout of linear formations 710. While notshown, the spacing of the protuberances may also be selected to allowthe formation of one or more minor linear formations as well. Of course,it should be noted that forming wires designed for use in themanufacturing processes disclosed herein are not limited to Cartesian ortriangular coordinate layouts, and any arrangement of protuberances maybe employed depending on the desired results of the first layer offibers on the nonwoven material produced.

Turning finally to FIG. 8, illustrated is an exemplary embodiment of aroofing shingle 800 manufactured using a nonwoven material as disclosedherein. The roofing shingle 800 may be manufactured by laminating abituminous material, for example, an asphalt-based layer, to form abituminous layer 810 (which may contain other materials as well) over anonwoven roofing mat 820 made from the nonwoven material as describedabove. As illustrated, the nonwoven roofing mat 820 includes first andsecond layers of fibers. Specifically, the first layer is composed ofdirectionally aligned fibers arranged in linear formations 830, whilethe second layer is formed over the first layer as is comprised ofrandomly dispersed fibers.

After being coated with the bituminous layer 810, granules 840 may beapplied to the top of the roofing shingle 800. The granules 840 arepressed into the bituminous layer 810 in any suitable manner, such asthe use of granule press. The roofing shingle 800, which is originallymanufactured in one continuous sheet, is cut from the continuous sheetby a cutting cylinder or similar device. After individual shingles 800are cut, each may be processed with commonly used machinery for handlingroofing shingles, such as a shingle stacker to form stacks of shinglesto be bundled for shipping. In alternative embodiments, the nonwovenmaterial used to form the fiber mat 810 may be used to form roofingmembranes, or other roofing materials, rather than roofing shingles, andthe disclosure herein should not be understood to be limited to anyparticular product.

In the exemplary embodiment of a roofing shingle, experiments of thetear strengths of roofing shingles employing both conventional nonwovensand the nonwoven fiber material disclosed herein were also conducted.Table 2 sets forth the results of such a comparison, again performedwith multiple samples (n) using the Elmendorf Tear Test.

TABLE 2 1.6 lb/ square mat 15% binder (Borden 413F) Tear, g Min, g Max,g σ Tear, g n COV, % Conventional 1,089 816 1,507 207 10 19.0 SingleLayer Nonwoven Novel 1,480 1,248 1,708 153 10 10.3 Two-Layer DirectionalNonwoven Percent ↑36% ↑53% ↑13% ↓46% Difference from Control

As is visible from the experimental results set forth in Table 2,roofing shingles manufactured with the disclosed nonwoven fiber materialhave better tear resistance over comparable conventional roofingshingles of the same weight. The percent coefficient of variation intear results [(standard deviation)/mean] demonstrates better uniformityin tear performance for the novel shingle product over comparableconventional shingle products. This is desirable for better processcontrol as well. Moreover, since the disclosed nonwoven materialtypically has stronger characteristics over comparable conventionalnonwoven materials, a roofing shingle having a significantly lowernonwoven fiber weight than roofing shingles made from conventionalnonwoven fiber materials, yet having the same tear and tensile factorsfound in the conventional shingle, may be constructed as disclosedherein.

While various embodiments of a multi-layer nonwoven fiber material, andrelated methods for manufacturing the material, according to theprinciples disclosed herein have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. The breadth and scope of the invention(s) should thus not belimited by any of the above-described exemplary embodiments, but shouldbe defined only in accordance with the following claims and theirequivalents. Moreover, the above advantages and features are provided indescribed embodiments, but shall not limit the application of the claimsto processes and structures accomplishing any or all of the aboveadvantages.

Additionally, the section headings herein are provided for consistencywith the suggestions under 37 CFR 1.77 or otherwise to provideorganizational cues. These headings shall not limit or characterize theinvention(s) set out in any claims that may issue from this disclosure.Specifically and by way of example, although the headings refer to a“Technical Field,” the claims should not be limited by the languagechosen under this heading to describe the so-called technical field.Further, a description of a technology in the “Background” is not to beconstrued as an admission that technology is prior art to anyinvention(s) in this disclosure. Neither is the “Brief Summary” to beconsidered as a characterization of the invention(s) set forth in theclaims found herein. Multiple inventions are set forth according to thelimitations of the multiple claims associated with this disclosure, andthe claims accordingly define the invention(s), and their equivalents,that are protected thereby. In all instances, the scope of the claimsshould not be constrained by the headings set forth herein.

1. A method for manufacturing a nonwoven fiber material, the method comprising: providing a three-dimensional forming wire comprising a screen and vertical protuberances projecting from the screen; dewatering a first plurality of chopped nonwoven fibers from a slurry such that they lay directionally aligned in at least three directions in a plurality of corresponding intersecting linear formations between the protuberances and on the same linear plane, a length of the protuberances determining a thickness of the linear formations, wherein the linear formations having substantially the same thickness as the thickness of the linear plane; and dewatering a second plurality of chopped nonwoven fibers from the slurry substantially simultaneously with the dewatering of the first plurality of fibers such that the second plurality of fibers lay randomly dispersed coextensive with the first plurality of fibers.
 2. A method according to claim 1, wherein dewatering the first plurality of fibers further comprises dewatering the first plurality of fibers to lay in the plurality of intersecting linear formations such that fibers within linear formations in one direction are laid randomly interlaced with fibers within linear formations in other directions at intersections of the linear formations.
 3. A method according to claim 1, wherein the overall length of each of the protuberances ranges from about 0.005 inches to about 0.375 inches.
 4. A method according to claim 1, wherein at least one of the first and second plurality of chopped nonwoven fibers are selected from the group consisting of: glass fibers, synthetic polymer fibers, ceramic and inorganic fibers, natural fibers, cellulosic fibers, and mixtures of any or all thereof.
 5. A method according to claim 1, wherein each of the chopped nonwoven fibers comprises a diameter ranging from about 0.00001 inches to about 0.0300 inches.
 6. A method according to claim 1, wherein each of the chopped nonwoven fibers comprises a length ranging from about 0.10 inches to about 1.5 inches.
 7. A method according to claim 1, wherein the slurry comprises a binding material and the binding material comprises about 5-30% of the nonwoven fiber material by weight.
 8. A method according to claim 1, wherein the slurry comprises a binding material and the binding material comprises an organic compound.
 9. A method according to claim 8, wherein the organic compound is selected from the group consisting of acrylic latex, urea-formaldehyde, SBR latex, acrylic emulsions, and mixtures thereof.
 10. A method according to claim 1, wherein the directionally aligned fibers constitute about 50% of the total thickness of the nonwoven fiber material.
 11. A method according to claim 1, wherein dewatering the first and second pluralities of fibers comprises forming the fiber material to have a tear-strength under the Elmendorf Tear Test of about 393 g mean tears when the fiber article has a weight of 1.6 lb/sq, and when 15% of the weight of the nonwoven fiber material is a binding material.
 12. A method according to claim 1, wherein an overall thickness of the nonwoven fiber material is about 0.035 inches, and the directionally aligned fibers comprise a thickness in the nonwoven fiber material of about 0.002 to 0.010 inches.
 13. A method according to claim 1, wherein the dewatering comprises using vacuum suction.
 14. A method according to claim 1, wherein the first and second plurality of fibers are collectively, horizontally dispersed to a substantially uniform thickness. 